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The Etiology and Natural History of Scheuermann’s Kyphosis

Gavin, Thomas M. CO

JPO Journal of Prosthetics and Orthotics: October 2003 - Volume 15 - Issue 4 - p S11-S16
SECTION I: ETIOLOGY AND NATURAL HISTORY
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Adolescent and pre-adolescent kyphosis will usually manifest into two groups: postural kyphosis and Scheuermann’s kyphosis. 1–7

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POSTURAL KYPHOSIS (ROUND BACK)

Postural kyphosis manifests as an increase in thoracic kyphosis while standing. Curve flexibility is seen when the patient stands erect as opposed to when the posture is relaxed. When the patient is prone or supine, the “deformity” resolves spontaneously. This nonprogressive condition is commonly seen in middle-school-aged children, especially girls, and almost always resolves by itself and requires no specific treatment; however, thoracic hyperextension exercises may be helpful. 6

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SCHEUERMANN’S DISEASE

ETIOLOGY AND NATURAL HISTORY

Scheuermann’s disease, or juvenile discogenic disease, was first described in 1921 by Holger Scheuermann, 5 who described it as a typically juvenile kyphotic disorder that could be distinguished from postural kyphosis on the basis of peculiar rigidity. Although many theories have been proposed, the cause of Scheuermann’s disease is unknown. Currently under investigation are the roles of juvenile osteoporosis, hereditary factors, biomechanical factors, and a variety of other causes. 6,8–14 The disease is identified radiographically by the appearance of vertebral wedging in the thoracic or thoracolumbar spine, and it disturbs the growth of the vertebral endplates (Figure 1). 1,3,5,8,10,13–18

Figure 1

Figure 1

Scheuermann’s disease is a condition of unknown cause that produces an increased thoracic kyphosis (>40°) with true structural changes within the thoracic vertebra with 5° of wedging in each of three adjacent vertebrae measured on side-view radiographs. 1,6–9,14,16,18–21 The apices are commonly between T7 and T9. 1,3,8,9,14,16,18 The localized deformity is usually painless. There is probably a strong hereditary pattern. 10 A subtype of Scheuermann’s disease occurs in the lumbar spine with apices between T10 and T12. 3,16,19 This is most common in late-adolescent boys who are involved in heavy lifting tasks. The changes of the vertebra and disc are considered to reflect the physical stress effects. 14

The incidence of Scheuermann’s disease varies according to the literature. Sorensen 7 reported a 0.4 percent to 8 percent incidence in the population. Bradford 9 noted an incidence as great as 10 percent. The incidences in males and females also vary according to the literature. Murray et al. 21 reported a male-to-female predominance of 2.2 to 1, whereas Winter 22 reported that the ratio was nearly equal.

Clinically, these patients range in age from 10 to 15 years. 3,9,15 Back pain and cosmesis are predominant clinical complaints. Upon forward bending, the patient with Scheuermann’s disease will present with an area of sharp angulation near the apex of the kyphosis, usually near T7. When standing, the patients appear “slouched” with a rounded shoulder appearance. Ascani et al. 8 noted that patients with Scheuermann’s disease often have a more athletic body stature and present with contracture of the pectoral muscles and hamstrings.

Bradford 9 suggested the following criteria be used in radiographically identifying Scheuermann’s kyphosis in the adolescent patient:

  • Irregular upper and lower vertebral endplates.
  • The apparent loss of disc space height.
  • Wedging of more than 10° in one or more vertebrae.
  • The presence of a hyperkyphosis greater than 40° (Figure 2).
  • Figure 2

    Figure 2

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INDICATIONS FOR TREATMENT

The only two documented methods of nonoperative treatment for Scheuermann’s are corrective casts and the Milwaukee brace. 2,22–27 Orthotic management has been shown to be effective in controlling a progressive curve in the adolescent patient. Adolescent patients typically present for medical attention because of pain or cosmetic deformity. Early treatment may be limited to observation and exercises, whereas patients who have kyphosis as great as 80° and growth remaining may benefit from bracing. 6,14

Treatment is dependent upon the magnitude of the deformity, pain complaints, and patient maturity. Observation is done for deformity of less than 60° and brace treatment for curves between 60° and 80° if the patient is skeletally immature. Surgery is occasionally required. 22,28–32

Sachs et al. 27 reviewed 132 patients and found an initial mean correction of 50 percent using the Milwaukee Brace. The mean full-time wearing period was 14 months, and the part-time period was 18 months. Apical wedging improved from a mean of 8.4° before treatment to 8.1° after treatment. For the more common thoracic form with apices superior to T8, the Milwaukee brace’s effectiveness has been documented, 6,18,24–28 and the brace is usually the treatment of choice (Figures 3 and 4).

Figure 3

Figure 3

Figure 4

Figure 4

Other types of orthoses have been used to treat thoracic Scheuermann’s disease, but there is a scarcity of literature to support their effectiveness. In addition, it is commonplace to treat thoracolumbar Scheuermann’s disease with a thoracolumbar spinal orthosis (TLSO), and many clinicians have experienced “good” results using this type of Scheuermann’s kyphosis, but there is little literature to support the effectiveness of this approach.

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WEARING TIME

There are differences in starting orthotic management for idiopathic scoliosis and Scheuermann’s disease. 25 A successful result in idiopathic scoliosis requires an actively growing child, whereas Scheuermann’s disease requires only active vertebral apophyses. 23,25 Therefore, orthotic treatment for Scheuermann’s disease is still effective after vertical growth cessation, as long as the vertebral apophyses are still immature.

In the current absence of a reliable correlation between hours of orthosis wear per day and outcome of orthotic treatment, 23 hours of wear per day is still the standard prescribed management of Scheuermann’s disease.

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WEANING

The decision to wean a patient from an orthosis for Scheuermann’s kyphosis is significantly different from that of weaning a patient from an orthosis for idiopathic scoliosis. Scheuermann’s disease may be divided into two categories: 1) patients who present with multiple uniform wedges of >5° over three or more vertebrae without the apical wedge being significantly greater than the adjacent wedges; and 2) patients with significant apical wedging. 2,25

For patients with multiple uniform wedges, curve correction is usually rapid, taking 9 to 18 months, and wedge healing is also rapid. Once correction is obtained, gradual weaning may ensue, with progressive cessation of the orthosis in 2- to 4-hour intervals. With correction maintenance, the total weaning phase may be accomplished in approximately 9 months. 25

For patients with excessive apical wedging, a longer period of wearing is required. Bradford et al. 23 reported that weaning should commence when significant apical wedge remodeling has occurred. In their study, patients had an average pre-orthosis apical wedging of 8.5°, and after orthotic management of approximately 34 months, had an apical wedging of 2°. For this category, remodeling of the apical wedge of 5° is considered the benchmark to begin weaning. Weaning should then proceed as previously described.

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CONCLUSION

Whereas the literature supports the usage of the cervicothoracic-lumbosacral orthosis for the treatment of Scheuermann’s kyphosis, 6,18,24–28 these studies are retrospective and difficult to compare because indications for usage, weaning procedures, and overall orthotic protocols vary. In addition, there is a case to be made that, in the absence of pain and progression, treatment may not be necessary for these patients because the condition of vertebral osteochondrosis (Scheuermann’s disease) is relatively benign when compared to the possible sequelae of untreated idiopathic scoliosis. 21

Evidence of the necessity to treat patients with Scheuermann’s kyphosis is weak in terms of weighing the cost risk-to-benefit factors. Is requiring a patient to wear an orthosis during their pre-adolescent and adolescent years worth the outcome of improved cosmesis? Will orthosis wearing truly treat the pain? If so, will the outcome be worth the orthosis wearing? Prospective clinical studies of the cervicothoracic-lumbosacral orthosis and TLSO treatment of Scheuermann’s kyphosis are still needed.

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REFERENCES

1. Aufdermaur M. Juvenile kyphosis (Scheuermann’s disease): Radiography, histology and pathogenesis. Clin Orthop 1979; 154: 166–174.
2. Bunch WH, Patwardhan AG. Clinical experience in orthotic treatment. In: Bunch WH, Patwardhan AG, eds. Scoliosis: Making Clinical Decisions. St. Louis: CV Mosby; 1989: 237–255.
3. Ferguson AB. The etiology of pre-adolescent kyphosis. J Bone Joint Surg [Am] 1956; 38: 149–157.
4. Ogden JA, Ganey TM, Sasse J, et al. Development and maturation of the axial skeleton. In: Weinstein SL, ed. The Pediatric Spine: Principles and Practice. Vol. 1. New York: Raven Press Ltd.; 1994: 3–69.
5. Scheuermann H. Kyfosis dorsalis juvenilis. Ugeskr laeger 1920; 82: 385–393.
6. Scoliosis Research Society website. Accessed: January 2002. http://www.srs.org/htm/library/review/review07.htm.
7. Sorensen KH. Scheuermann’s Juvenile Kyphosis: Clinical Appearances, Radiography, Aetiology and Prognosis. Copenhagen: Munksgaard; 1964.
8. Ascani I, Ippolito E, Montanaro A. Scheuermann’s kyphosis: histological, histochemical and ultrastructural studies. Presented at 17th Annual Meeting, Scoliosis Research Society, Denver, Colorado, September 22, 1982.
9. Bradford D. Vertebral osteochondrosis (Scheuermann’s kyphosis). Clin Orthop 1980; 122: 83–90.
10. Halal F, Gledhill RB, Fraser C. Dominant inheritance of Scheuermann’s juvenile kyphosis. Am J Dis Child 1978; 132: 1105–1107.
11. Ippolito E, Bellocci M, Montanaro A, et al. Juvenile kyphosis: an ultrastructural study. J Pediatr Orthop 1985; 5: 315–322.
12. Ippolito E, Ponseti IV. Juvenile kyphosis: histological and histochemical studies. J Bone Joint Surg [Am] 1981; 63: 175–182.
13. Schmorl G. Die pathogenese der juvenilen kyphose. Fortschr geb Rontgen 1930; 41: 359–383.
14. Wenger DR, Frick SL. Scheuermann kyphosis. Spine 1999; 24: 2630–2639.
15. Ali RM, Green DW, Patel TC. Scheuermann’s kyphosis. Curr Opin Pediatr 1999; 11: 70–75.
16. Blumenthal SL, Roach J, Herring JA. Lumbar Scheuermann’s. A clinical series and classification. Spine 1987; 12: 929–932.
17. Scoles PV, Latimer BM, DiGiovanni BF, et al. Vertebral alterations in Scheuermann’s kyphosis. Spine 1991; 16: 509–515.
18. Tribus CB. Scheuermann’s kyphosis in adolescents and adults: diagnosis and management. J Am Acad Orthop Surg 1998; 6: 36–43.
19. Fon GT, Pitt MJ, Thies ACJ. Thoracic kyphosis: range in normal subjects. Am J Roentgenol 1980; 134: 979–983.
20. Lambrinudi C. Adolescent and senile kyphosis. BMJ 1934; 2: 800–804.
21. Murray PM, Weinstein SL, Spratt KF. The natural history and long-term follow-up of Scheuermann kyphosis. J Bone Joint Surg [Am] 1993; 75: 236–248.
22. Winter R. The treatment of spinal kyphosis. Int Orthop 1991; 15: 265–271.
23. Bradford DS, Moe JH, Montalvo FJ, et al. Scheuermann’s kyphosis and roundback deformity: results of Milwaukee brace treatment. J Bone Joint Surg [Am] 1974; 56: 740–758.
24. Gutowski WT, Renshaw TS. Orthotic results in adolescent kyphosis. Spine 1988; 13: 485–489.
25. Lonstein JE. Orthotic treatment of spinal deformities. In: American Academy of Orthopaedic Surgeons, eds. Atlas of Orthotics. St. Louis: CV Mosby; 1985: 371–385.
26. Montgomery SP, Erwin WE. Scheuermann’s kyphosis: long term results with Milwaukee brace treatment. Spine 1981; 6: 5–8.
27. Sachs B, Bradford DS, Winter R, et al. Scheuermann kyphosis: follow-up of Milwaukee brace treatment. J Bone Joint Surg [Am] 1987; 69: 50–57.
28. Bradford DS, Moe JH, Montalvo FJ, et al. Scheuermann’s kyphosis: results of surgical treatment by posterior spine arthrodesis in twenty-two patients. J Bone Joint Surg [Am] 1975; 57: 439–448.
29. Herndon WA, Emans JB, Micheli LJ, et al. Combined anterior and posterior fusion for Scheuermann’s kyphosis. Spine 1981; 6: 125–130.
30. Ponte A, Siccardi GL, Ligure P. Scheuermann’s kyphosis: posterior shortening procedure by segmental closing wedge osteotomies, abstracted. J Pediatr Orthop 1995; 15: 404.
31. Speck GR, Chopin DC. The surgical treatment of Scheuermann’s kyphosis. J Bone Joint Surg [Am] 1986; 68: 189–193.
32. Taylor TC, Wenger DR, Stephen J, et al. Surgical management of thoracic kyphosis in adolescents. J Bone Joint Surg [Am] 1979; 61: 496–503.
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SECTION I: ETIOLOGY AND NATURAL HISTORY

POINTS OF CONSENSUS: IDIOPATHIC SCOLIOSIS

ETIOLOGY

The etiology of IS remains unknown today, but current research suggests its cause is multifactorial. We recognize IS to be an extremely complex disorder, in which multiple factors may come into play, making curve progression in any given individual difficult to predict. In fact, the variability observed in factors such as curve patterns, curve flexibility, and age of onset suggests the “multifactorial” nature of IS is so pronounced that it may be more useful to think of IS as encompassing two or more distinct etiologies. Our inability to identify the distinct etiology a patient may be presenting with makes curve progression in any given individual, and thus the likelihood of successful orthotic treatment, difficult to predict. It is important for the treating orthotist to have a general understanding of the various factors thought to be associated with the condition. There currently is no evidence in the literature that suggests the development of IS can be prevented in one who is otherwise predisposed to have a progressive curve before treatment. Thus, the orthotist should be knowledgeable enough to quell caregiver or patient concerns about the possibility of the scoliosis being preventable, such as by the avoidance of heavy school backpacks or poor posture.

For the purpose of communicating with peers and other health care professionals, the treating orthotist should understand the differences among infantile, juvenile, and adolescent onset IS, and that these should not be confused with congenital scoliosis.

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GOALS FOR ORTHOTIC TREATMENT

The goal of using an orthosis in the treatment of IS is to stop curve progression and minimize negative cosmetic consequences, thus preventing the need for surgical stabilization of a curve. In some instances in which surgery is anticipated, an orthosis may be beneficial to the patient by postponing the surgical stabilization.

The orthotist should appreciate the three-dimensional aspects of scoliotic spine deformity. For instance, one should recognize the propensity for thoracic scoliosis to be hypokyphotic, unless proven otherwise. The ability to envision and understand the three-plane deformities that may exist with scoliosis should influence the appropriate application of corrective forces for satisfactory in-orthosis correction.

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KEY POINTS FOR UNDERSTANDING RISK OF PROGRESSION

THE RELATIONSHIP OF GENDER AND CURVE PROGRESSION

The incidence of scoliosis with smaller curves that do not require treatment beyond observation is similar between boys and girls. Progression of small curves to a size requiring treatment is more prevalent in girls than boys by a factor of approximately 7 to 1.

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THE RELATIONSHIP OF CURVE SIZE AND MATURITY WITH CURVE PROGRESSION

In general, the younger the child and the larger the curve, the greater the risk for curve progression. However, other factors such as curve pattern can contribute to the risk for curve progression. In any individual patient, a worsening of the condition can be thought of as a race between curve progression and maturation of the growth process. In general, the cessation of spinal growth should naturally halt the progression of a scoliotic curve that is less than approximately 50° in size. There are two primary reasons the orthotist and other key health care providers should understand the risks for curve progression: 1) To communicate accurate information with the patient and caregivers regarding the strategy and timing of orthotic treatment; and 2) To enable a critical review of the literature because not all publications include patients of equal risk for curve progression.

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STATEMENT OF EFFICACY OF ORTHOTIC TREATMENT

Orthoses can be efficacious in the treatment of IS, and their use is the only nonsurgical treatment method shown to positively alter the natural history of the disease. Although there are limitations in the current literature investigating the true etiology and natural history of the condition, there is strong evidence that orthotic treatment can prevent curve progression in most of those who would otherwise experience curve progression if left untreated.

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RESEARCH PRIORITIES
  • More research is needed to identify which patients, at a younger age, with diagnoses of IS are more likely to demonstrate significant curve progression. Having this ability can potentially justify earlier intervention of orthotic treatment, which should increase the likelihood of a successful outcome while not simultaneously “overtreating” the patient population.
  • More research is needed to identify which patients have a more “malignant” etiology (or combination of factors) that may respond poorly to orthotic treatment.
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CRITERIA FOR ORTHOSIS PRESCRIPTION

Structural curves with apices cephalad to the seventh thoracic vertebrae (T7) are less likely to respond to bracing than are those with curve apices at or caudad to this level. The amount of in-orthosis correction is expected to be less the more cephalad the curve. The current literature does not support the efficacy of bracing curves with apices above T7 as thoroughly as curves caudad to this level.

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RESEARCH PRIORITY
  • More investigation is needed to understand orthotic design alternatives and the effectiveness of orthotically treating curves with apices cephalad to T7.
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CRITERIA FOR ORTHOSIS USE DISCONTINUATION

DISCONTINUING TREATMENT BECAUSE OF MATURITY

Because girls typically reach skeletal maturity at a younger chronological age than do boys, a criteria for orthosis discontinuation will differ depending on patient gender. That said, multiple factors can be considered in assessing maturity, so only general guidelines are possible.

Girls should ideally be at least of Risser 4 maturity, 18 months to 2 years beyond menarchal, and/or with clear cessation of significant growth (as measured by consecutive height measurements using consistent techniques throughout the duration). Curve size and location should help influence the timing of this decision (ie, larger, more unbalanced curves may benefit from a more delayed discontinuation because of maturity).

For boys, the primary adolescent growth spurt is later in life, so their risk for curve progression extends to an older chronological age. Extenuating factors like those referenced for girls (curve size and location) also exist for boys, but boys are believed to be served by an orthosis to Risser 4, preferably Risser 5, with greater emphasis being given to a documented significant decrease in growth velocity.

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DISCONTINUING TREATMENT BECAUSE OF CURVE PROGRESSION OR OTHER FACTORS

Once an orthosis has been prescribed to prevent curve progression in adolescent IS, it is important to continue orthotic treatment until either skeletal maturity is achieved or the clinic team agrees the treatment is ineffective or no longer necessary because of maturity. The amount of in-orthosis correction, the patient’s perceived ability to wear the orthosis, and evidence of curve progression are important factors during the consideration of discontinuation of orthosis use in an otherwise immature patient.

With respect to discontinuing orthotic treatment because of curve progression, we concur with the SRS’s position, which states: “Surgery for IS is suggested when curve magnitude is 50° or more in either the previously untreated patient or in one who fails orthotic treatment. Surgery is undertaken with two goals in mind. The primary one is to prevent spine deformity progression and the secondary one is to diminish spinal deformity. The natural history of IS during adulthood is one of continued progression if the curves tend to be more than 50° at the end of growth.” Thus, although 45° is considered the upper limit of orthotic efficacy, there can be exceptions to treating some with curves of 50° or higher; namely for those with infantile or juvenile scoliosis, for which there can be an advantage of slowing curve progression during periods of significant growth in an effort to delay the need for surgical stabilization. This is in recognition of the “crankshaft phenomenon,” for which it is sometimes necessary for an orthopedist to surgically fuse the anterior spine in addition to the posterior when a significant amount of remaining growth is expected. Using an orthosis to delay or slow curve progression in a young child may postpone the need for surgical stabilization to the extent that only a posterior fusion is required. This can yield significant benefits to the patient.

“Weaning” from an orthosis, defined as recommending a period during which the patient can decrease the amount of time spent in the orthosis, may be beneficial to the patient in two distinct ways: 1) Long-term weaning (last 6 months of wear) can be considered as a treatment modality in response to risk for curve progression. For example, an adolescent who is thought to be approaching skeletal maturity and whose curve appears stable, but whose level of maturity is not to the degree that would justify complete orthosis discontinuation would be a candidate for long-term weaning; 2) Short-term weaning may serve as a way to minimize the risk for back pain when an orthosis is no longer necessary to prevent curve progression because of skeletal maturity. For example, once orthotic treatment is deemed unnecessary because of maturity, a patient may serially decrease the amount of time an orthosis is worn on a daily basis during a period of 1 to 4 weeks.

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RESEARCH PRIORITY
  • There needs to be a better understanding of the optimal time to discontinue the use of an orthosis in the treatment of adolescent IS so as to assure a positive outcome with long-term follow-up.
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POINTS OF CONSENSUS: SCHEUERMANN’S KYPHOSIS

ETIOLOGY

We recognize the definition of Scheuermann’s disease as a condition of unknown cause that produces an increased spinal kyphosis with true structural changes. To differentiate true Scheuermann’s disease from postural roundback, we recognize the criteria described by Sorensen, 7 namely, that three adjacent vertebrae must each be wedged at least 5°. Orthoses can be useful in treating this disease for the more typical vertebral apices of T7–T9, and also for subtype apices of the lower thoracic, thoracolumbar, or lumbar spine.

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TREATMENT GOAL

The orthotic treatment goal for Scheuermann’s kyphosis is to serially diminish the size of the curve to a degree that will provide permanent correction of the deformity. We concur with the Scoliosis Research Society’s position: “Observation is done for deformity of less than 60° and orthotic treatment for curves between 60° and 80° if the patient is skeletally immature.” Curves larger than 80° may benefit from other therapies (eg, Risser cast) as a precursor to orthotic treatment.

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DISCONTINUATION OF ORTHOSIS USE

For thoracic curves, the goal should be to reduce the kyphosis to an angle of less than 50° before discontinuation of orthosis use. Post-treatment deterioration (increase) has been demonstrated in the literature, so the amount of kyphosis ideally should be decreased beyond a size that may otherwise be considered acceptable. For example, it may be necessary to reduce a curve to 40° to 45°, as documented by an out-of-orthosis film when skeletal maturity is thought to be achieved, to obtain a long-term result of 50° to 55° of kyphosis.

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THE ROLE OF PHYSICAL THERAPY

Unlike the treatment of scoliosis, active correction of a kyphosis by the patient’s volitional control within an orthosis, especially with a Milwaukee-style orthosis, is thought to play a role in the correction of the deformity. For this reason, the role of a physical therapist to instruct the patient on methods to strengthen the extensors of the spine may be beneficial.

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RESEARCH PRIORITIES
  • Increase our understanding of the complete role of physical therapy as an adjunct to orthotic treatment of Scheuermann’s kyphosis.
  • Better understand the efficacy of bracing Scheuermann’s kyphosis with a Milwaukee-style orthosis versus a molded, thermoplastic TLSO. By extension, there needs to be a better understanding of active versus passive in-orthosis correction in both designs.
  • There needs to be a better understanding of the limits of orthotic efficacy with respect to varying degrees of deformities (eg, both Cobb angles and curve location).
© 2003 American Academy of Orthotists & Prosthetists